Aldosterone influences free intracellular calcium in human mononuclear leukocytes in vitro.
Mineralocorticoid receptors have been detected in human mononuclear leukocytes (HML) and a physiological effector mechanism was demonstrated subsequently by which aldosterone is able to prevent the loss of intracellular sodium, potassium and cell water during incubation in an aldosterone-free medium. In the present paper, free intracellular calcium, [Ca2+]i, was measured in HML from normal subjects by Quin-2 and Fura-2 fluorescence after incubation for 1 h at 37 degrees C in RPMI-1640 medium. In fresh HML, [Ca2+]i was 54 +/- 15 nM (Fura-2, mean +/- SD, n = 26). After incubation without aldosterone, [Ca2+]i in HML was 118 +/- 27 nM (Quin-2, n = 11) and 50 +/- 13 nM (Fura-2). After incubation with 1.4 (Fura-2) or 2.8 nM (Quin-2) aldosterone, [Ca2+]i was 139 +/- 38 nM (Quin-2, P less than 0.05 compared with value after incubation without aldosterone) and 57 +/- 11 nM (Fura-2, P less than 0.00001). The Kd-value for dose-response curve was 0.4 nM. The effect of aldosterone was antagonized by N-ethyl-isopropylamiloride, but not by canrenoate, canrenone, cycloheximide and actinomycin D. It was absent in a sodium-free buffer. Corticosterone and hydrocortisone were active as agonists. These results show that aldosterone exerts an effect on the [Ca2+]i in HML in vitro which could be involved in hemodynamic responses to mineralocorticoids if also present in cardiovascular tissues.
Wehling
M
M
Medizinische Klinik, University of Munich, FRG.
Käsmayr
J
J
Theisen
K
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000494:pharmacology*; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000097:blood*; D002191:Canrenoic Acid / Q000494:pharmacology; D002192:Canrenone / Q000494:pharmacology; D003345:Corticosterone / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D008875:Middle Aged
D003609:Dactinomycin; D000450:Aldosterone; D002192:Canrenone; D000584:Amiloride; D002191:Canrenoic Acid; D003513:Cycloheximide; D002118:Calcium; C039614:ethylisopropylamiloride; D003345:Corticosterone; D006854:Hydrocortisone